Hot melt adhesive guns are known for application of melted thermoplastic adhesive onto a work surface on which the adhesive solidifies to form a required bond. In one known type of hot melt adhesive gun which is substantially manual in operation, the front end of a meltable stick of solid adhesive is inserted into a chamber and forced into engagement with an electrically heated plate as the operator presses with his thumb on the back of the stick. The stick is melted and liquid adhesive flows out of the gun through a nozzle onto a bonding surface. To stop the flow of adhesive, the operator must pull back on the stick to disengage it from the heater plate.
Although such manually operated types of hot melt adhesive guns are quite simple in design and can be used anywhere there is a source of standard electrical power for energizing the heater, the quantity of adhesive present in the stick is limited and is not sufficient for many industrial applications. The stick of adhesive is also subject to breakage, such as by lateral pressure by the operator, which detracts from the overall utility of the gun.
Another type of known hot melt guns usually employed in industrial applications employs a cartridge of normally solid thermoplastic adhesive contained within a chamber in which the cartridge or portion thereof is heated and melted and by pneumatic action urged through a pneumatically valved nozzle for dispensing onto the work surface. A particularly effective gun of this type is the subject of copending patent application Ser. No. 438,730, filed Feb. 1, 1974, now U.S. Pat. No. 3,877,610, assigned to the assignee of this invention. Such pneumatically operative guns of course require a source of pressurized air or other generating gas which limits their portability and are relatively expensive. Although very useful, for heavy duty high volume applications, there is a need for a hot melt adhesive gun more suited to relatively light duty low volume usage and in situations where it is considered useful to have a completely portable gun.